Recently, considerable effort is being expended to develop wings capable of generating tractive force for the purposes of powering a user on a variety of vehicles that are tethered solely by flexible lines. Such wings can generally be considered kites. The development of kites capable of generating significant force has made possible numerous recreational pursuits. For example, kite surfing or kite boarding refers to a sport involving the use of a wind powered wing to pull the participant on a vehicle across a body of water. Similar sports involving the use of appropriately configured vehicles to traverse sand, earth, snow and ice are also being pursued. One having skill in the art will also recognize that wind powered wings can be used in any number of other applications, whether recreational or practical. With the development of these applications has come an increasing demand for kites having improved characteristics and ease of use.
One type of kite that has achieved popularity is a leading edge inflatable (“LEI”) kite, typically comprising a semi-rigid framework of inflatable struts or spars that support a canopy to form the profile of the wing. This basic design is taught by U.S. Pat. No. 4,708,078 to Legaignoux, et al. The development of the LEI kite is generally credited with spurring the development of modern kite surfing due to its ability to be relaunched from the water's surface.
LEI kites by design allow the inflation and deflation of the struts. As discussed above, a primary benefit of the LEI design is the resulting buoyancy of the kite that facilitates relaunching the kite from the water. Further, the use of separately inflated struts offers an important safety characteristic. Since each strut is isolated from each other, the failure of one does not lead to loss of pressure in the others. Thus, if one rib strut were to puncture, the leading edge and the remaining struts would stay inflated. If the kite were in the water when the failure occurred, the inflated remaining struts would keep the kite afloat. If the kite were still flying when the failure occurred, the user likely would be able to continue flying the kite, return to shore and then land the kite. If the failure were to occur in the leading edge, it is unlikely that the kite could still be flown, but the remaining inflated rib struts would continue to provide buoyancy.
Inflation and deflation also contributes significantly to the convenience and practicality of the LEI kite design. A kite can be deflated for storage and transport, a virtual necessity given that typical sizes of recreational traction kite range from about 5 square meters to over 20 square meters.
Despite the benefits offered by the inflatable design, certain drawbacks have become apparent. Conventional LEI kites require that the leading edge and each rib strut be separately inflated and deflated. Accordingly, a user needs to separately operate a valve for each strut for either inflation or deflation. For inflation, the user needs to fit the pump nozzle into the valve, pump sufficient air into the strut, and remove the nozzle and close the valve without losing a significant amount of air pressure in the strut. This can be challenging if a check valve is not used, because it is easy to lose significant air pressure while removing the pump nozzle and closing the valve. Although the valve stem can be pinched to reduce air loss, this requires effort, especially under adverse conditions such as cold. Even if the valve is equipped with a check mechanism, such as a ball stopper, the operation often allows pressure loss anyway and the check mechanism can also hinder pinching the valve stem, adding to the chance of significant air pressure loss. For deflation, the user may only need to open each valve. However, if some type of check valve is employed, such as a ball stopper, the user must manipulate each valve to let the air out of the strut. Furthermore, many users opt to use their pump to speed the deflation of the struts as well. Naturally, this requires that the pump nozzle be fit into the valve for each strut to be deflated. Each of these valve operations must be multiplied by the number of separate struts in the kite. Smaller LEI kites often have three to five rib struts in addition to the leading edge. Larger kites often have seven or more rib struts. Although not an great burden, manipulating the valves and fitting the pump nozzle for each strut represents a significant portion of the overall time required to prepare the kite for use or to deflate the kite for transport and storage.
Using separate valves for each strut also has the potential to undermine the performance of the kite. Since the user must independently inflate and then remove the pump nozzle before closing the valve for each strut, there is a significant chance that the struts will not be inflated to the same pressure. As one having skill in the art will appreciate, this can cause the performance of the kite to suffer. For example, the rigidity of the kite depends in part upon the structure imparted by the strut framework. If there are significant differences in inflation pressure between the rib struts, the kite will not behave in a consistent manner and will have decreased stability.
Accordingly, it is an object of the present invention to provide a LEI kite design the offers increased convenience by reducing the time and effort required to inflate the kite.
It is also an object of the present invention to provide a LEI kite design that helps ensure maximum performance consistency.
It is another object of the present invention to provide a LEI kite design increases the stability of kite at relatively lower inflation pressures.
It is yet another object of the present invention to provide a LEI kite design that maintains the safety benefits of isolated air chambers.